Lähdemerkki

Lähdemerkki is a Finnish term that translates to "source mark" or "origin mark." It is commonly used in cartography and surveying to denote a specific point of origin for a survey or a geographical feature. These marks are often established by national mapping agencies or local authorities to ensure accuracy and consistency in mapping and land administration.

In practice, a lähdemerkki can be a physical marker placed on the ground, such as a metal bolt embedded in concrete, a stone monument, or a specially constructed benchmark. These markers are meticulously surveyed and their coordinates are precisely determined. They serve as reference points for subsequent measurements, allowing surveyors to establish the exact location of property boundaries, infrastructure projects, and natural features. The establishment and maintenance of lähdemerkit are crucial for the integrity of spatial data.

The concept of a lähdemerkki is fundamental to geodetic control networks. By having a reliable system of origin marks, it is possible to connect different surveys and ensure that maps and spatial databases are geographically consistent. This is important for a wide range of applications, including urban planning, environmental monitoring, and the creation of accurate navigational charts. The precision and permanence of lähdemerkit are key to their function as fundamental points in spatial referencing.